This project has been directed towards the design, preparation and evaluation of novel polymeric vehicles that can control the release of ophthalmic drugs. Hydrogels based on several synthetic and naturally-derived polymeric and monomeric units, including poly(vinylpyrrolidone-co-[meth]acrylic acid)s, N-isopropylacrlamide or 2-hydroxyethyl methacrylate and different types chitosan, were synthesised, and the effects of hydrogels' network structure and composition upon swelling properties, adhesion behaviour and drug release characteristics were examined. These novel materials were formulated as either ophthalmic inserts or as nanosuspensions, and were investigated both in vitro and in vivo for their ability to act as controlled release vehicles for ophthalmic drug delivery. Comparative in vitro studies employing a range of common ophthalmic drugs (chlaramphenicol, atropine, norfloxacin or pilocarpine) informed the selection of drug-specific carrier compositions for the controlled delivery of these compounds, and indicated that some of these materials have a high potential for the delivery of sparingly water-soluble actives. In vivo (rabbit model) experiments involving the delivery of pilocarpine showed that chitosan-based hybrid polymeric networks containing 2-hydroxyethyl methacrylate may be potentially useful carriers for the delivery of this therapeutic agent.